The French exchequer has been ordered to pay 10 billion euros to big companies after the country's highest judicial authority struck down a tax imposed by the previous government on dividend payouts.

Earlier this month the Constitutional Council declared the three-percent tax on dividends, introduced by President François Hollande's government in 2012, illegal on the grounds that it violated the "principle of equality before the law and public levies".

On Wednesday government spokesman Christophe Castaner announced that the government will have to pay back 10 billion euros, half of it to just 13 firms.

He blamed "legal amateurism" on the part of the previous government for "the biggest tax gift ever handed to companies in this country".

The finance ministry may include the payments in an updated budget plan, or mini-budget, later in the year, he said.